Blend flour, beer, eggs, pepper, onion powder, and turmeric well, but do not over beat. Batter should "plop" from a spoon. If it is too thin, thicken with additional flour.
Dry each piece of fish with paper towels. Heat oil to 375 'F in an automatic deep-fryer.
Dip fish pieces in batter and deep-fry for 5-10 minutes. Turn occasionally.
Drain fish on paper towels and serve immediately with tartar sauce.